Performance Evaluation of Hydro-Estimator Technique-Based Rain Products from INSAT-3DR During Indian Summer Monsoon 2020

Hydro-Estimator (H-E) method-based rainfall products from INSAT-3DR are operationally available at the web portal of the India Meteorological Department (IMD). These high spatial (4 km) and temporal (30 min) resolution products not only play a significant role in monitoring monsoonal rain over India and the surrounding ocean but also show importance in assessing several meteorological events such as tropical cyclones, floods, cloud bursts and thunderstorms. Thus, a comparison of these rain products with in situ observations and other satellite data is important to evaluate their performance. This study details about the validation procedures and discusses the performance of H-E technique-based rain products from INSAT-3DR over India and surrounding oceans during the Indian summer monsoon (June–September) 2020. The performance of products is evaluated using two sets of data (1) in situ network of IMD rain gauges over India and (2) Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (GPM) (IMERG) products. Results show that H-E well captures the spatial distribution of rain as depicted by rain gauges and IMERG. H-E shows a probability of detection of > 95% and a false alarm rate of < 25% with in situ rain gauges’ observations on a monthly scale. It provides a correlation of 0.4 and a root mean square error of 54.48 mm/day with respect to IMERG over India and the surrounding ocean. The present study provides a detailed evaluation of the H-E rain for its worthiness for various applications.